Known structures for supporting high tension power transmission lines present several problems. One problem arises because the structures are generally made of inductive material, the induction caused by the high voltages in the transmission lines decreasing the power carrying capacity of the system. Some support structures are made of wood, but these structures are usually small and expensive to maintain. Larger poles are typically made of steel, and these are conductive and present the problem of induction and the risk of a short to ground. Similar problems exist throughout the high tension infrastructure, for example, in the structures used in substations.
The typical solution to these problems is to space the high tension lines from the support structure by significant distances with large insulators. These insulators, however, are expensive and require the structures themselves to be large as well.
Another solution that has been proposed is to make the support structure of plastic materials that are not inductive. These structures have not been successful because such structures having adequate strength are quite expensive. Further, plastic towers are flexible, which makes them vulnerable to excessive vibration in windy conditions. These vibrations are transmitted to the power lines causing them to break and resulting in often serious damage. Another drawback to the use of plastics is that they degrade significantly in the harsh environment to which the structures are exposed, particularly UV-radiation from the sun.
It has also been proposed to make utility poles of steel-reinforced concrete. These poles are also very susceptible to the weather, particularly moisture, which causes the steel to rust and degrade the concrete by spalling.